1. Field of the Invention
The present invention relates to a soft magnetic film, and in particular to a soft magnetic film mainly utilized in a magnetic pole for a thin film magnetic head.
In this specification, the content of an element in alloy is determined based on the atomic percentage.
2. Description of the Prior Art
For example, an iron cobalt nitrogen (FeCoN) alloy layer is well known. The FeCoN alloy layer realizes a relatively higher saturation magnetic flux density such as 2.4 [T] approximately. In addition, if the FeCoN alloy layer is laid over the nickel iron (NiFe) ferromagnetic layer, a good magnetic anisotropy can be obtained in the FeCoN alloy layer. See IEEE Transactions on Magnetics, Vol. 36, No. 5, September 2000, pp2506–2508, for example. The FeCoN alloy layer on the NiFe ferromagnetic layer exhibits a soft higher saturation magnetization.
A still higher saturation magnetization is required for the upper and lower magnetic poles in a thin film magnetic or inductive write head utilized to write bit data in a hard disk drive (HDD), for example. A higher saturation magnetization leads to generation of a stronger magnetic field for recording at the write gap of the thin film magnetic head. A stronger magnetic field for recording largely contributes to a still increased recording density. A higher saturation magnetization is expected in a soft magnetic film.
For example, the aforementioned FeCoN alloy layer may be utilized as the upper magnetic pole of the thin film magnetic head. However, the aforementioned FeCoN alloy layer should be accompanied by a substratum of the NiFe ferromagnetic layer for establishment of a predetermined magnetic anisotropy. Accordingly, the NiFe ferromagnetic layer has to be interposed between the upper magnetic pole and the non-magnetic spacer or gap layer. Since the NiFe ferromagnetic layer only exhibits the saturation magnetization of 1.1 [T] approximately, the utilization of the FeCoN alloy layer fails to lead to establishment of a stronger magnetic field for recording.